The present invention relates to imaging devices and methods, pertinent to electromagnetic energy in visual and other spectra, aimed at capturing and reproducing substantially all image information in a relevant spectrum.
In order to achieve truly full-spectrum images, it has long been deemed necessary to detect the full color gamut of the image, and not just the conventional three Red-Green-Blue (RGB) band-pass filtered colors. Most cameras detect color by separating the image into these three components, passing each component through an absorption filter and thence onto three detectors. Two-thirds of the light energy is lost in this process.
Recent studies have shown that while any color can be created by combining three colors, not all colors can be generated or detected by the use of a specific set of three colors. In other words, our reliance on metameric RGB color space models to create a full palate of colors is flawed.
Most electronic imaging detectors are composed of a large set of tiny light-sensitive semiconductors. Each cell of the set responds to the amplitude of the incoming light. Being photon detectors, the cells cannot in themselves distinguish color and thus several sets are used: for example, one each for red, green, and blue.
Electromagnetic radiation, which includes light, x-rays, and radio waves, can be characterized mathematically as waves as well as photons. At long wavelengths, e.g. radio frequencies, photons have little energy and the wave properties predominate for analysis. At shorter wavelengths, e.g. light, the photons have considerable energy and are currently used exclusively in designing light detecting systems.
It is known in the art that heterodyning can be used for detecting the spectral composition or spectral signature of complex infrared electromagnetic waveforms. In this technique, “an infrared source is combined with a laser local oscillator,” in the manner described by Kostiuk (see references), “and focused on an infrared photometer, where the difference frequency between the source and laser frequencies is generated . . . . The resultant intermediate frequency . . . is in the radio region of the electromagnetic spectrum and it preserves the intensity and spectral information of the infrared spectrum. It can be analyzed using radio techniques, e.g., filter banks, autocorrelators, or acousto-optic spectrometers . . . . These determine the absolute spectral resolution.” Similar techniques are known in the art for detecting the composition of millimeter wavebands. These heterodyning techniques essentially use optical methods to determine the absolute spectral resolution downshifted to the radio-frequency band. Such methods are too crude to resolve small increments of spectrum in the visible light wave region.